Should USC be worried about Sam Darnold?

LOS ANGELES -- Given the way then-redshirt freshman Sam Darnold and USC had finished last season, it wasn't hard to envision them steamrolling all of their opponents come the following fall. Accordingly, Darnold -- the red-headed, strong-armed, square-jawed face of perhaps the most glamorous college football program in the country -- came into the year as a Heisman Trophy front-runner. His -- and the Trojans' -- ascendancy seemed assured with another year of experience.

Through four games this season, it hasn't quite worked out that way.

But for a whistle-to-whistle throttling of Pac-12 rival Stanford in Week 2, the Trojans' offense has virtually sleepwalked through its other games, including an uninspired 30-20 victory over unranked California on Saturday.

In that game at Berkeley, Darnold finished 26-of-38 for 223 yards and two touchdowns, along with an interception, his seventh of the year and a total that left him tied for third in the nation. He also failed to connect on any of the eight pass attempts that traveled 15 or more yards in the air, with his only "completion" at that distance going to Bears defensive back Josh Drayden.

"It's 100 percent my fault," Darnold said after the game. "I'm not getting the ball out far enough on deep routes -- or whether it's balls being tipped, not seeing the D-linemen and him getting a big paw on the ball to tip it in the air."

Darnold and the Trojans will face another stiff challenge on Friday night at No. 16 Washington State (10:30 p.m. ET, ESPN and ESPN App), where Cougars coach Mike Leach appears to finally have a defense capable of complementing his annual offensive fusillade led by senior quarterback Luke Falk. After five seasons of units that have only once ranked higher than 81st in the nation in total yards allowed, Leach will deploy the country's 12th-ranked defense against USC.

While speaking with media earlier this week, Leach praised Darnold as a college passer -- "I think he's mature, really just kind of mentally together for a guy that's his age" -- but was much less effusive about his current NFL prospects. "I don't think he is today," Leach said, responding to a question about Darnold's readiness to play professionally, before going on a screed about how most young players aren't prepared to play in the NFL.

Regardless, the 6-foot-4, 220-pound Darnold is widely considered the top prospect for the 2018 NFL draft, including by ESPN's Mel Kiper Jr. and Todd McShay. And it's not hard to understand why Darnold is thought of so highly: He has the arm strength, accuracy, athleticism and poise of a much-more experienced quarterback. Those tools obscure the fact that Darnold has only made 14 career starts, winning all but his first one at Utah a year ago. Now, defenses finally have enough film on Darnold to counterpunch.

USC offensive coordinator Tee Martin said opposing defenses have almost literally tried every look in the playbook against Darnold, hoping to rush him into a mistake or flush him out of the pocket.

"We're seeing everything," Martin said. "He's being challenged."

Of course, all of the Trojans' struggles on offense can't be pinned Darnold: They came into the fall needing to replace all but two of the starters on the offensive line, including both tackles. That line was a key factor in him being the least-sacked quarterback in the Pac-12 last season. Darnold also has missed receivers JuJu Smith-Schuster and Darreus Rogers, who combined for 41 percent of the team's receptions and 45 percent of the receiving yards in 2016.

All of those changes have led to Darnold forcing the issue more than he did last season. He told local media this week that, yes, he has gotten "impatient" at times but still feels he has improved. Some of the numbers back that up: Darnold actually has been more accurate this season, in terms of off-target percentage, from 9 percent in 2016 to 7 percent this year.

In fact, it's most likely that his spike in interceptions -- from nine last season to seven in four games already this fall -- has been a product of defenses blitzing him less, creating crowded passing lanes as he increased his number of throws downfield (20 percent of his pass attempts have been 20 or more yards compared to just 12 percent in 2016), according to ESPN Stats and Information research. Compounding those troubles, Darnold also has had bad luck with tips and drops.

"There are going to be so many times that he makes a great play, where you go, 'Wow,'" USC coach Clay Helton said. "Every now and then, he is going to have a forced throw, and you have to take the good with the bad."

There have been glimpses of the USC offense that blistered Penn State in January's Rose Bowl game: The Trojans displayed all of their potential to fulfill the preseason hype in the 42-24 victory over Stanford in their second game of the season.

It was then, in the comfort of the Los Angeles Coliseum, that the Trojans looked most like the swashbuckling offensive power they were predicted to be over the summer. Darnold completed 80 percent of his passes for 316 yards -- for which he earned Pac-12 Offensive Player of the Week honors -- as USC rolled up its most total offensive yards (623) against Stanford in at least 45 years. The game seemed a precursor to bigger things, not all that different from his record-breaking performance (473 total yards) in the Rose Bowl.

But against Texas the following week, Darnold didn't come alive until the fourth quarter and the two overtimes it took to eventually hold off the unranked Longhorns.

And at sun-splashed Memorial Stadium against California on Saturday, facing a defense under first-year coach Justin Wilcox that was allowing about half as many points per game as the previous season, the Trojans followed much the same formula.

USC was outgained 416 yards to 356, needing six turnovers from its defense and a 17-point stretch early in the fourth quarter to pull away from the Bears.

After the game, in the bowels of the stadium, a glum-looking Darnold admitted he had felt some of the pressure from the newly improved California defense.

"There was such a relentless pursuit," he said. "I felt a little bit of the pressure, but I think it's mostly our fault for not connecting on some of the deep balls and some of those opportunities."

Afterward, Helton and Martin weren't dissuaded from the belief that Darnold and the Trojans were capable of meeting all of those rosy expectations. The season is long, they said, and these subpar performances and hard-fought wins will only came in handy down the stretch.

"This is what championship football looks like," said Martin, who would know, as he quarterbacked 1998 national champion Tennessee. "You go to the Rose Bowl, you're not a secret anymore and you're going to get everybody's best. That's what these games look like."

They'll likely get another one of those games this Friday in Pullman, where waiting for them will be a Washington State squad off to its first 4-0 start in 17 years and a defense that ranks among the nation's leaders in sacks (fourth), tackles for a loss (eighth) and defensive touchdowns (second).

"I don't think I've played up to my standard, by any means," Darnold said in his weekly "Season of Sam" podcast. "But I think as the season gets rolling, as I find my flow with the receivers and protections, I think I'll just continue to improve."